Crysis

Overview

Ransomware:Win32/Crysis (also widely known as Dharma) is a highly prolific, long-running Ransomware-as-a-Service (RaaS) family. It is infamous for its aggressive targeting of Small and Medium Businesses (SMBs) through the brute-forcing of Internet-exposed Remote Desktop Protocol (RDP) services.

Understanding Crysis (Dharma)
To the victim organization, a Crysis infection is devastating. Critical servers and workstations are rapidly encrypted, with filenames appended with extensions like `.dharma`, `.wallet`, or `.crysis`, along with an attacker email address. For incident responders, Crysis represents a failure in network perimeter security. Unlike ransomware distributed via complex exploit kits or phishing, Crysis operators rely heavily on simple, manual network penetration techniques to gain interactive access to the victim's network before deploying the payload.

Execution, RDP Brute-forcing, and Encryption
The primary initial access vector for Crysis is exploiting poorly secured RDP endpoints (TCP 3389) (`T1133`). Attackers use automated scanners to find open RDP ports and brute-force Administrator credentials (`T1110.001`). Once logged in interactively, the attacker manually disables antivirus using tools like Process Hacker or IObit Uninstaller (`T1562.001`). They then deploy the Crysis payload. The ransomware uses `vssadmin.exe` to delete shadow copies (`T1490`) and utilizes a combination of RSA and AES cryptography to lock the files (`T1486`). It often establishes persistence via Registry Run keys to ensure any new files created after reboot are also encrypted.

Indicators of Compromise & Impact
The impact is a total halt of business operations. EDR platforms must alert on the rapid execution of `vssadmin` or the manual disabling of security agents. Network logs will show massive, sustained RDP brute-force attempts leading up to the infection. The presence of encrypted files with an email address embedded in the extension (e.g., `document.txt.id-[ID].[email@domain.com].dharma`) is the definitive IoC.

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to the MITRE ATT&CK framework:

Generated Detections (Boilerplate)

These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.

YARA Rule

rule MALWARE_WIN_CRYSIS {
    meta:
        description = "Detects Crysis (ransomware)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "crysis" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Crysis Activity
id: 426f683afd9e59651b41498fde8df326
status: experimental
description: Detects generic indicators of the crysis malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*crysis*"
    condition: selection
level: medium

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. Instantly sever the infected endpoint or server from the network by pulling the physical cable; the attacker likely has active, interactive RDP access.
2. Do not reboot the server if it is actively encrypting; rebooting can destroy cryptographic material in RAM.
3. Audit firewall rules immediately to identify and close all Internet-facing RDP ports (TCP 3389) to prevent reinfection.
4. Begin the incident response process to restore the data from secure, offline, and immutable backups.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not pay the ransom. Paying funds the RaaS ecosystem and there is no guarantee the affiliates will provide a working decryption tool.
2. Avoid restoring from backups onto the same server without first completely wiping it and securing the RDP access vector.

References & External Analysis

• Search "crysis" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: ransomware)

Explore other malware families in the same category:

• Mousedisable
• Umbald
• E2F3F4D
• Streamer
• Ctqc

Machine-readable

Get this profile as JSON: https://jordanricky1604-ship-it.github.io/malware-families-catalog/api/crysis.json

Ecosystem & Interactive Environments

This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.